It is proposed to test the levels of phospholipase B activity in the lungs and brains, and the numbers of eosinophils in the bone marrow, of nonsensitized and sensitized rats after challenge with Angiostrongylus cantonensis. In earlier work with Trichinella spiralis and Nippostrongylus brasiliensis, elevated levels of the enzyme were related temporally with expulsion of adult worms from the small intestine, suggesting its involvement in a common (nonspecific) expulsion mechanism. The proposed study of A. cantonensis, with its unique life cycle, will permit a determination of whether this association (elevated enzyme levels and loss of worms) exists for a worm that is not expelled via the intestinal tract. BIBLIOGRAPHIC REFERENCES: Larsh, J.E., Jr., Ottolenghi, A., and Weatherly, N.F. 1975. Trichinella spiralis: phospholipase in sensitized mice after challenge. Experimental Parasitology 37, 233-238. Ottolenghi, A., Kocan, A.A., Weatherly, N.F., and Larsh, J.E., Jr. 1975. Nippostrongylus brasiliensis: phospholipase in nonsensitized and sensitized rats after challenge. Experimental Parasitology 33, 96-104.